1. Field of the Invention
This invention relates to a bilge blower for use with watercraft. In particular, the invention relates to a bilge blower that attaches to a watercraft""s bilge drain when the watercraft is onshore.
2. Description of the Related Art
One hazard for people who operate motorized watercraft is that bilges in watercraft can fill with fuel vapor. This can happen when a watercraft is onshore, as well as when the craft is in operation. This vapor tends to be highly flammable and even explosive. A small spark, for example a spark thrown off by the craft""s engine, can ignite the fuel vapor, resulting in a fire or explosion.
For these reasons, the United States Coast Guard requires that certain motorized vessels with permanently installed gasoline engines and fuel tanks be equipped with internal bilge blowers. A blower of this type is a permanent part of the vessel in which it is installed and is typically powered by the vessel""s electrical system. In order to alleviate the potential for a fuel vapor fire or explosion, a vessel""s bilge blower must be run for at least four minutes prior to starting the vessel""s engine. In addition, the blower should be run at all times when the vessel""s engine is idling. Use of such bilge blowers has reduced the number of fuel vapor fires and explosions.
Despite the success of the use of bilge blowers, fuel vapor problems still exist. When a motorized watercraft is stored onshore, fuel vapor can accumulate in the bilge. If the watercraft is covered and parked in the sun, the temperature in the watercraft can rise dramatically. This increased temperature can contribute to even more buildup of fuel vapor in the bilge. While the watercraft is in storage, the required internal bilge blower typically is not being run, so the vapor can continue to accumulate as long as the craft is being stored.
As a result, after a watercraft has been stored for any significant period of time, an accidental spark or flame could result in a fuel vapor fire or explosion. For example, a person with a cigarette could set off a fire or explosion. Likewise, static electricity could ignite the fuel vapor. Even a defective bilge blower could throw off a spark, triggering a disaster. This danger exists until the watercraft has been taken out of storage and the craft""s internal bilge blower has been run.
Fuel vapor is not the only troublesome substance that can accumulate in a watercraft""s bilge during storage. Another hazard is the accumulation of water vapor. If the vessel is stored for any extended period of time, this water vapor can provide an ideal environment for molds, fungus, mildew, and other infestations. Again, a watercraft""s internal bilge blower provides little relief from this hazard because the blower typically is not run while the craft is in onshore storage.
A solution is needed for the problem of buildup of fuel and water vapor in a watercraft""s bilge during storage. Because the solution should function while the vessel is in storage and therefore largely unattended, the solution should be capable of operating for an extended period of time without maintenance or other operator intervention.
The invention addresses these problems with a bilge blower that attaches to a watercraft""s bilge drain. All watercraft that have a bilge include a bilge drain for draining water from the bilge. When the watercraft is onshore, this bilge drain provides a good access point for drawing fuel and water vapor from the bilge.
Accordingly, one aspect of the invention is a bilge blower for a watercraft such as a power boat. The bilge blower includes a blower unit and a power unit. The blower unit can be removeably attached to a bilge drain on the watercraft. The power unit supplies power to the blower unit. When the blower unit is attached and power is supplied, the bilge blower draws air and vapor from the watercraft""s bilge through the bilge drain.
The blower unit preferably includes a fan with a brushless motor. A brushless motor is used to reduce the likelihood of sparks which could ignite any fuel vapor.
In the preferred embodiment, the blower unit includes a housing that attaches to the bilge drain with a threaded connector. Most bilge drains have one-half inch National Pipe Taper (NPT) female openings shaped to receive one-half inch National Pipe Taper male drain plugs, which are typically shaped like one-half inch NPT threaded pipes. Thus, the threaded connector provides an easy and convenient method for attaching the bilge blower to the bilge drain.
Preferably, the housing is made of brass, aluminum, or stainless steel. The housing also can be made of plastic.
In order to provide power over an extended period without operator intervention, the power unit preferably generates power using solar cells. With this embodiment, though, the blower unit will not run if insufficient light is present. Alternatively, one or more batteries could be used. However, batteries might have to be replaced. Thus, in a preferred embodiment, both solar cells and one or more rechargeable batteries are used in conjunction with each other. When sufficient light is present, the solar cells supply power both to run the blower unit and to recharge the batteries. When less light is present, the batteries can run the blower unit.
Preferably, the solar cells are removably mountable on an anti-cavitation plate of a motor for the watercraft. The anti-cavitation plate provides a convenient and easily-accessible location for mounting the solar cells. Alternatively, the solar cells can be mountable on a tongue of a trailer for the watercraft. The tongue mounted embodiment is particularly useful for watercraft that lack outboard motors (and thus anti-cavitation plates).
Because solar cells and other sources of long-term power can be relatively expensive, a locking mechanism can be provided for locking the power unit in place on the watercraft or on a trailer for the watercraft.
The invention also includes a method of using the bilge blower to draw air and vapor from a watercraft""s bilge through the craft""s bilge drain, thereby reducing fuel and water vapor in the bilge.